I have to say, I have never seen an augmented chord used in the fashion these guys did in that song (All My Loving). If I had to guess, maybe it's an old music hall technique Paul heard from his father when he was growing up and his father played in bands. Any body else have any thoughts on the use of the augmented chord in that fashion?

In "Michelle" you get the same descending line in the harmony, stepping down by semi-tones:

"All my lovin...I will send to you""I will say the only words...."

Except with "Michelle" it keeps going - F,E,Eb,D,Db, landing finally on the dominant C. But in both examples the augmented chord is generated by the second step down.

Nicely done, Nelson. What I love about this song is the alternation between Fminor and Fmajor. It has the effect of brightening and darkening the mood. First shadow, then sunlight, then shadow.... It's such a beautiful piece.

(Couldn't find a youtube of good ol' Jim Croce himself doing his song. I think the original was in Dm, just like Michelle, but maybe this guy is up half a step ...).......Also, the same chord progression, with the famous Pilzkopf augmented 2nd chord, in that classic forever we all know and love - "A Heartbeat (It's a Love Beat!)" by the DeFranco family!!

I'll just make some comments on a couple of other things you wrote earlier:

"To the best of my knowledge, an E aug (E-G#-C) has the same notes as a C aug (C-E-G#), has the same notes as a G# aug (G#-C-E), they are just different inversions of each other. I think there may only be 4 truly different augmented chords:"

Right, if you move the shape up the frets, you get an inversion of the original at every fourth step.

And diminished sevenths repeat every third step, so there's only three of those. The three that Nelson played in his "Michelle" tutorial, in the instrumental outro, are all inversions of each other!

Augmenteds again:"I've usually seen it used as a 5th chord on the way back to the root chord - like the first chord in "Oh, Darling"."

I was playing one of their early songs on my guitar a few weeks back where there was an augmented chord like that one, played instead of the dominant fifth. But I can't remember which song. Which was it? It's annoying me that I can't pin it down.

I'll just make some comments on a couple of other things you wrote earlier:

"To the best of my knowledge, an E aug (E-G#-C) has the same notes as a C aug (C-E-G#), has the same notes as a G# aug (G#-C-E), they are just different inversions of each other. I think there may only be 4 truly different augmented chords:"

Right, if you move the shape up the frets, you get an inversion of the original at every fourth step.

And diminished sevenths repeat every third step, so there's only three of those. The three that Nelson played in his "Michelle" tutorial, in the instrumental outro, are all inversions of each other!

Augmenteds again:"I've usually seen it used as a 5th chord on the way back to the root chord - like the first chord in "Oh, Darling"."

I was playing one of their early songs on my guitar a few weeks back where there was an augmented chord like that one, played instead of the dominant fifth. But I can't remember which song. Which was it? It's annoying me that I can't pin it down.